Are Chaos and Tikal dead?

At the end of Sonic Adventure, after Sonic had freed Chaos of the turmoil that was in him for thousands of years, Chaos and Tikal went up into the sky and disappeared.

Since then, Chaos and Tikal have only been seen as camoes or in non canon games.

Did the two go to Sonic's version of Heaven, or just some place else and are still alive?